Field of Invention
The present invention relates to underground water-storage vaults, systems, and methods for installing the same.
Brief Description of Related Art
Conventional underground water-storage vaults are constructed using flexible water-impermeable films/membranes, which are commonly referred to in the art as geomembrane material. The water-impermeable films can be single- or multi-layer constructions and are generally provided as continuous rolls of flat material of various widths as desired for particular applications. These applications can include the collection of rainwater for subsequent irrigation use and/or to provide a water source for landscaping water features, e.g. pond-free waterfalls.
Conventional methods for installing underground water-storage vaults generally begin with excavating a suitably sized hole in the ground. A sheet of geotextile fabric material and a sheet of water-impermeable membrane material are folded and manipulated by hand to line the opening in the ground and thereby form a sump. Next, a desired number of plastic matrices, which are typically assembled on-site, are placed into the lined opening in the ground. Typically, a pump housing unit for receiving a pump is placed in the lined opening, wherein the plastic matrices are adjacent to, or partially surrounding, the pump housing unit. A pump is then placed in the pump housing unit. The remaining sheets of geotextile fabric and membrane are gathered around the plastic mastrices, and then soil or other material is then backfilled outside the geotextile fabric and membrane. The backfill material laterally presses against the outside surface of the membrane to compact the matrices in a block arrangement inside the water-impermeable membrane. The matrices provide structural support to the flexible water-impermeable membrane so that the membrane does not collapse under the pressure from the backfill, and so that the sump can retain a certain volume to accept the influx of water.
In these conventional methods, the water-impermeable membrane is provided as a roll of flexible flat membrane material, and installation therefore includes attempting to conform the flat membrane material to the contoured surfaces of the excavated hole. This process necessarily results in excess membrane material bunching up and folding upon itself as the membrane material is conformed in the contours of the excavated hole.
In one conventional application, the excess membrane material is drawn up over the top of the matrices and welded to itself on the installation site in order to seal the membrane material and enclose the sump. In another conventional application, the membrane material is not sealed, but is left open at the top. A water-permeable geotextile fabric is applied over the open sump to cover the matrices. The geotextile fabric is then covered with a permeable layer of gravel, pavers and/or soil in order to conceal the water reservoir below the grade of the soil. In this scenario, any water that permeates the geotextile fabric due to gravity will then accumulate in the sump. Openings are cut into the water-impermeable membrane at the installation site to accommodate plumbing fittings to connect to water inlet and outlet conduits.
While the membrane material is flexible and thus can be advantageously rolled up to save space and costs for transportation purposes, the current methods of installing underground water-storage vaults are nevertheless time-consuming, imprecise, and result in the waste of membrane material due to the bunching and folding of the membrane material as it is conformed over the contours of the excavated hole. These excessive amounts of membrane material used to form the sump are unnecessary and result in the waste of money, time, and precious natural resources used to make the membranes. Improvements are needed.